Sink Bowl

How do I patch a crack in the bowl of my plastic bathroom sink? And build wells thick bowl?
This economic sink molded in a mobile home. First, the good finish in the sink started to peel and mold. later, a crack appeared in the form X (crack lines are approximately 1 / 2 inches long). It seems that the sink is the thickness of eggshells just there. For now, apply a coat of liquid nail sealant in the bottom of the sink, and painted several layers of clear nail polish (paint) inside the crack, but I'm sure there may be permanent, and can not support a pressure down on the sink when I clean. It might help if I knew what type of plastic they are made well?
the sink is made of PVC. New cost well under $ 50 and the valve as little as $ 20. should monitor the size of the pool though. edit it in the sink. If you want a direct replacement for test. Www.mobilehomestuffstore.com